In a cellular network, several states and corresponding behaviors may be defined for a plurality of wireless transmit/receive units (WTRUs) and a network including at least one base station (BS). In a disconnected mode, a WTRU may be aware of its rough geographical area and may notify the network of any change in the geographical area so that the network knows where the WTRU is to be paged. The WTRU may monitor for paging during the disconnected mode. In order to know its geographical area, the WTRU may need to recognize at least one cell in its immediate area, or search for other cells to obtain sufficient information to recognize its area.
When necessary, the WTRU may switch to a connected mode from the disconnected mode. In order to do so, the WTRU may identify the strongest cell in the area and receive the necessary information to determine its access mode. The WTRU may use a common (contention based) channel to access a cell. After some interactions, the WTRU may establish connections (service flows) as necessary in the connection mode. Once connections are established, the WTRU may have resources assigned to it and may request additional bandwidth as necessary.
It may be desirable for a WTRU to collaborate in the relaying of data to/from the network, or to communicate data locally without data flows to/from a base station. Various procedures are needed to support such collaboration by enabling the WTRU, possibly assisted by the network, to identify and maintain an association with at least one other WTRU.